Venetian blinds comprise a plurality of substantially identical generally flat elongated slats disposed in a parallel array. Each slat comprises a pair of elongated apertures at equal preselected distances from the opposed respective ends of the slat. The longitudinal axes of the elongated apertures are substantially parallel to one another and orthogonal to the longitudinal axis of the associated slat. The apertures in each slat are disposed to be substantially in register with the corresponding apertures in the other slats of the array.
Venetian blinds further comprise a pair of interlaced flexible support structures extending transverse to the slats in the array and generally in line with the respective apertures formed in the slats. Each interlaced support structure comprises a pair of runners disposed on opposite respective sides of the slats and transverse supports extending between the runners at equally spaced locations therealong. The runners are operative to support each respective slat and to adjust the angular alignment of the slats relative to the runners. The transverse supports may be alternately staggered on opposite respective sides of the apertures in the slats.
The blinds further comprise pull cords extending through the registered apertures. One end of each pull cord and one end of each runner in the interlaced support is fixedly secured to the bottom most slat which may be more rigid than other slats in the array. The opposed ends of the pull cords and the runners extend into a channel in which an elongated control rod is rotatably mountable.
Control cords extend from the channel to permit adjustment of the blinds. In particular selected movement of the control cords enables rotation of the rod to generate corresponding longitudinal movement of the runners relative to one another, thereby altering the angular alignment of the transverse supports and the slats relative to the runners. The pull cords which pass through the aligned apertures in the slats also extend from the channel. Appropriate adjustment of the pull cords enables the controlled collapsing or extension of the array of slats defining the blinds.
The slats of venetian blinds have been formed from many materials, including wood, plastic and metal. Blinds having thin metal slats are considered very desirable in view of their light weight, their ability to reflect light and heat and their aesthetic appearance. The prior art metal blinds typically are manufactured from a coil of thin metal strip material. The coil is unwound into an apparatus which cuts slats to specified lengths and punches the apertures therein at specified distances inwardly from the opposed ends of each slat. The punch forming of the holes in the metal slats must be very precise to avoid creating burrs or edge irregularities in the metal material that could wear the cords passing therethrough or that could injure a person dusting, adjusting, or otherwise manipulating the blinds. This prior art apparatus may also be operative to form the metal material into an arcuate cross section along the length of the slat. The slats are interlaced with the interlacing support and the cord is directed through the apertures. The cords and the interlacing are then appropriately connected to the control means in the upper channel of the venetian blinds.
Although the prior art venetian blinds and apparatus for making blinds are extremely desirable, it has been necessary to custom manufacture every venetian blind to match the window dimensions of the consumer. This custom manufacturing has been perceived as a marketing limitation in that many consumers prefer to receive products substantially at the time the request for the product is made. This virtual instantaneous availability of venetian blinds generally has not been available in the prior art.
The prior art includes modular wooden blinds to facilitate fabricating blinds to match specified window dimensions. Examples of these modular blinds are shown in U.S. Pat. No. 4,333,509 and U.S. Pat. No. 2,170,938. Although these modular approaches could be attempted for wooden or plastic blinds, they can not be adapted to blinds formed from thin metal slats.
In view of the above, it is an object of the subject invention to provide a partly assembled kit of venetian blind components that can be finished to specified window dimensions.
It is another object of the subject invention to provide a method for making venetian blinds wherein several final assembly steps can be completed substantially at the point of purchase.
It is an additional object of the subject invention to provide a discontinuous manufacturing process for venetian blinds wherein a plurality of manufacturing and assembly steps can be carried out at a first location and wherein the remaining steps can be carried out at the point of purchase.
It is a further object of the subject invention to provide apparatus for final manufacturing steps for venetian blinds.
Still another object of the subject invention is to provide a precision aperture forming apparatus for forming registered apertures in the metal slats of venetian blinds.
Yet another object of the subject invention is to provide an assembly of apparatus for cutting partially assembled metal venetian blinds to specified dimensions and for forming registered apertures in the metal slats of the blinds.